1. Field of the Invention.
The present invention relates to a magnetically actuated device for controlling the flow of material through an internal bodily conduit at a closure point commonly called a sphincter.
2. Description of the Prior Art.
Artifical sphincters have been advanced in the prior art, and primarily the ones that are in use utilize an inflatable cuff surrounding a conduit to obturate material flow. In creating the localized pressure necessary to overcome the material back pressures, the cuff-type devices also will tend to obstruct the normal flow of blood in the conduit walls, and thus long term useage of cuff-type artificial sphincters is not viable. The continuous ring of pressure without adequate blood flow results in scarring and localized tissue damage.
A type of a magnetically actuated artificial sphincter is shown in United States Pat. No. 3,926,175 that shows a cuff having a platen section that is actuated by magnetic force to press against a conduit around which the cuff is placed. An external electromagnet is utilized for providing the force, and thus the device is not totally implantable, and is made so it will snap to a locked position and must be snapped back to an open position. While the device is made to apply forces only on two opposite sides of the conduit that it is surrounding, rather than in a noose-like complete ring in order to prevent necrosis, the unit is still difficult to operate, and varying the closing pressures is difficult because the magnet used is for actuation of an over center actuating device.
U.S. Pat. No. 4,024,S55, issued May 24, 1977 to Bucalo describes a magnetic filament which may be implanted in the form of a pair of coils on opposite sides of a body tube such as a urethra. The coils both can be permanent magnet materials, or one can be a permanent magnet and the other a filament that has magnetic properties. The coils that are implanted are polarized so that they attract each other for the purposes of pinching the conduit or urethra closed. Then, in order to open the body conduit it is necessary to provide an external unit that creates a magnetic field which alters the polarity of the implanted coils so that the coils repel each other to open the tube. When drainage is over, the external power unit is used to return the implanted coils to their original polarity. It can be seen that such devices have limitations in the force that can be generated, and require the use of external controls for operation. Further, as a practical matter, controlling the pressure on the body conduit using these devices is difficult, so that leakage or dripping can occur, or the coils can cause closure which is too tight and then will cause damage to the tissue as well.
A magnetically actuated device for controlling a tube that carries fluid flow to or from different organs of the body of a human is shown in U.S. Pat. No. 4,053,952, but this uses a type of valve arrangement which has a coil with oppositely facing contact members on opposite sides of the tube. When current is supplied to demagnetize or magnetize permanent magnets installed, the tube can selectively be blocked or opened. An external current of substantial value is required in order to operate the unit, and while it is indicated that power consumption is low, there still is a need for external power. The device shown in Patent '952 can be used as a pump as well, in one form of the invention by alternately magnetizing and demagnetizing provided permanent magnets.
Magnetically controlled plugs have been advanced for controlling incontinence, and such devices are shown in West German Patents DE27l7607 and DE 3139811. Other similar plug devices are known, but they do not use magnetic forces for collapsing or closing off an internal bodily conduit.